1. Field of the Invention
The invention generally relates to the technical field of electrical installations and, more particularly, to electrical transformers, phase shifters and inductors of high rated power, such as those commonly used in energy distribution networks.
2. Description of the Related Art
Electrical installations, such as transformers, inductors or switching devices, represent node points in an energy distribution network, and in times of crisis these node points can be potential targets of attack for destructive strikes from outside. Such strikes include, e.g., attacks front surrounding terrain by fire from small arms, explosive charges detonated in the vicinity of the electrical installation, or even grenade or bomb fragments. The side walls of a tank filled with fluid are particularly vulnerable, in this case. If these side walls are hit by bullets, depending on the intensity of the missile effect, a leak can occur. However, even if the tank remains tight, a pressure wave cars propagate in a liquid-filled tank, causing safety devices to shut down the installation. In both cases, the energy supply can be adversely affected by the attack.
DE 37 23 048 A1 discloses, for example, object protection for a transformer of high rated power, where the side walls of the transformer tank are internally reinforced with protective plates to protect against external mechanical effects. The protective plates are welded onto the side walls on the inside and consist of a special steel for cushioning fragments and missiles. One disadvantage here is that the protective reinforcement is weakened in the region of the welded seam. A further disadvantage is that, in the case of bullets, pressure waves propagate in the liquid-filled tank, which can result in the transformer being shut down by safety devices. The energy supply is then interrupted at least temporarily.